#include <bits/stdc++.h> using namespace std; using ll = long long; using ull = unsigned long long; using pii = pair<int, int>; #define fi first #define se second #define pb push_back #define all(v) (v).begin(),(v).end() #define rep(i,a,b) for(int i=(a),_##i=(b);i<_##i;++i) #define foru(i,a,b) for(int i=(a),_##i=(b);i<=_##i;++i) #define ford(i,a,b) for(int i=(a),_##i=(b);i>=_##i;--i) #define r0p(i,b) for(int i=0,_##i=(b);i<_##i;++i) #define fileio(TASK) if (fopen(TASK".INP","r")) {\ freopen(TASK".INP","r",stdin); freopen(TASK".OUT","w",stdout); } template<typename T, typename S> bool mini(T &x, const S &y) { return x > y ? x = y, true : false; } template<typename T, typename S> bool maxi(T &x, const S &y) { return x < y ? x = y, true : false; } const int max_n = 1000011; int n; struct Point { int x, y, id; void input(int i) { cin >> x >> y; id = i; } inline void flip() { swap(x, y); } bool operator<(const Point &ot) const { return x < ot.x || (x == ot.x && y < ot.y); } } point[max_n]; void input() { cin >> n; r0p (i, n) { point[i].input(i); } } namespace sub2 { bool valid() { return n <= 16; } void process() { #ifdef ON_LOCAL cerr << "> Running subtask 1-2" << endl; #endif const int SUPER_MASK = (1 << n) - 1; vector<int> set_x(max_n, 0), set_y(max_n, 0); foru (msk, 1, SUPER_MASK) { bool all_light = true; for (int um = SUPER_MASK ^ msk; um > 0; um -= um & -um) { int i = __builtin_ctz(um); int cntx[2] = {0, 0}, cnty[2] = {0, 0}; for (int m = msk; m > 0; m -= m & -m) { int j = __builtin_ctz(m); if (point[j].y == point[i].y) ++cntx[point[j].x >= point[i].x]; if (point[j].x == point[i].x) ++cnty[point[j].y >= point[i].y]; } if ((cntx[0] > 0 && cntx[1] > 0) || (cnty[0] > 0 && cnty[1] > 0)) continue; all_light = false; break; } bool too_many = false; for (int m = msk; m > 0; m -= m & -m) { int i = __builtin_ctz(m); ++set_x[point[i].x]; ++set_y[point[i].y]; too_many = too_many || (set_x[point[i].x] > 2 || set_y[point[i].y] > 2); } if (!too_many && all_light) { #ifdef ON_LOCAL cerr << "> Found answer" << endl; #endif r0p (i, n) cout << (msk >> i & 1); cout << '\n'; return; } for (int m = msk; m > 0; m -= m & -m) { int i = __builtin_ctz(m); --set_x[point[i].x]; --set_y[point[i].y]; } } } } namespace sub3 { bool valid() { unordered_map<int, int> mp; r0p (i, n) { ++mp[point[i].x]; if (mp[point[i].x] > 2) return false; } return true; } void process() { #ifdef ON_LOCAL cerr << "> Running subtask 3" << endl; #endif r0p (i, n) cout << '1'; cout << '\n'; } } namespace sub6 { bool valid() { return true; } vector<int> set_x, set_y; vector<bool> put_light; void process_light(vector<int> &group) { if (set_x[point[group[0]].x] == 2) return; int sz = group.size(); int first = -1; r0p (i, sz) { int id = group[i]; if (!put_light[point[id].id] && set_y[point[id].y] < 2) { put_light[point[id].id] = true; first = point[id].id; ++set_x[point[id].x]; ++set_y[point[id].y]; break; } } ford (i, sz - 1, 0) { int id = group[i]; if (!put_light[point[id].id] && set_y[point[id].y] < 2 && set_x[point[id].x] + (point[id].id != first) <= 2) { put_light[point[id].id] = true; ++set_x[point[id].x]; ++set_y[point[id].y]; break; } } } void solve() { sort(point, point + n); vector<vector<int>> group; r0p (i, n) { if (group.empty() || point[group.back().front()].x != point[i].x) group.emplace_back(); group.back().pb(i); } int left_ptr = 0, right_ptr = group.size() - 1; while (left_ptr < right_ptr) { process_light(group[left_ptr]); ++left_ptr; if (left_ptr < right_ptr) { process_light(group[right_ptr]); --right_ptr; } } if (left_ptr == right_ptr) process_light(group[left_ptr]); } void process() { #ifdef ON_LOCAL cerr << "> Running subtask 4-5-6" << endl; #endif set_x.assign(max_n, 0); set_y.assign(max_n, 0); put_light.assign(n, false); solve(); r0p (i, n) point[i].flip(); set_x.swap(set_y); solve(); r0p (i, n) cout << (put_light[i] ? 1 : 0); cout << '\n'; } } void preprocess() { if (sub2::valid()) { sub2::process(); return; } if (sub3::valid()) { sub3::process(); return; } if (sub6::valid()) { sub6::process(); return; } } int main() { fileio("SLAMP") cin.tie(nullptr)->sync_with_stdio(false); input(); preprocess(); return 0; }

Main.cpp: In function 'int main()':
Main.cpp:15:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |   freopen(TASK".INP","r",stdin); freopen(TASK".OUT","w",stdout); }
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:200:3: note: in expansion of macro 'fileio'
  200 |   fileio("SLAMP")
      |   ^~~~~~
Main.cpp:15:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |   freopen(TASK".INP","r",stdin); freopen(TASK".OUT","w",stdout); }
      |                                  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:200:3: note: in expansion of macro 'fileio'
  200 |   fileio("SLAMP")
      |   ^~~~~~